(662g) Navigating the Route of Polyester Textiles to Net-Zero Emissions

The rise in emissions and consequent global warming pose significant challenges, urging nations worldwide to take decisive action, as demonstrated by the commitments made in the Paris Agreement [1]. Recognizing industries, particularly the textile sector, as major contributors to emissions underscores the imperative of addressing this issue [2]. Adding to the emissions, the impact of plastic pollution originating from the textile industry extends across vast distances. Specifically, discarded plastic clothing is estimated to have dispersed at least 1.4 quintillion (or one million trillion) plastic microfibers into the ocean [3]. Hence, textiles present a significant environmental threat. Amongst these textiles, polyester fiber stands out as the most utilized, significantly contributing to emissions. This is primarily due to its heavy reliance on fossil-based resources and energy-intensive production processes [4]. Many industries are aiming to achieve net-zero emissions owing to these factors [5]. This underscores the urgent need for mitigation strategies that simultaneously address environmental impact and economic feasibility.

In response to these pressing challenges, this research aims to chart a pathway toward achieving net zero emissions while considering economic factors. Initially, we conduct a comprehensive life cycle assessment (LCA) and techno-economic analysis of the polyester fiber value chain, delineating a cradle-to-gate system boundary. This
approach captures key manufacturing stages where significant improvements can be made. By employing comparative LCAs, we evaluate various alternative polyester molecules, such as Polyethylene terephthalate (PET), Polytrimethylene terephthalate (PTT), and Polylactic acid (PLA), alongside different fossil-based and biobased raw materials, thereby comparing their environmental footprints and economic efficiencies. Our findings indicate that PLA exhibits minimal emissions, while the conventional polyester manufacturing process from PET proves to be cost-efficient.

Utilizing multi-objective optimization and Pareto Analysis, we endeavor to identify optimal combinations of alternatives that strike a balance between emission reduction and cost efficiency. Our investigation reveals that a synthesis of PLA and PET production processes yields valuable trade-off insights for stakeholders, facilitating progress toward net-zero emissions. We also find that excluding PLA as an alternative in the optimization problem impedes the path to achieving net-zero emissions and increases the cost of the optimal combination. To address these issues, we identify cost and emission hotspots within the conventional route and propose solutions to mitigate them. Our analysis identifies electricity production from fossil routes and energy production from fossil resources as major emitters, contributing significantly to the life cycle cost. Therefore, we propose the incorporation of renewable energy alternatives and carbon capture and utilization processes as decision variables in the problem, offering promising avenues for achieving net-zero emissions in a financially sustainable manner. By examining trade-offs involved in incorporating these technologies, we find that utilizing wind energy, a combination of PLA and PET, carbon capture by direct air capture, and chemical looping, and converting the captured CO2 to ethylene are part of the trade-off solutions that lead to more cost-efficient and environmentally friendly outcomes.

In addition, we plan to extend the life cycle to encompass the use phase and recognizing consumers as significant stakeholders. We will explore diverse end-of-life scenarios to attain zero waste, emphasizing circularity. Furthermore, we aim to integrate emerging technologies and project future scenarios to develop a roadmap to achieve net-zero emissions [6]. Proposed multiperiod planning strategies provide a comprehensive roadmap toward achieving net-zero emissions, considering economic factors alongside environmental objectives. Ultimately, this research aims to provide comprehensive solutions to enhance the environmental sustainability of the polyester fiber value chain, contributing to the broader goal of fostering a greener future for the textile industry while ensuring economic viability.

References:
1. Savaresi, A. (2016). The Paris Agreement: A New Beginning? Journal of Energy & Natural Resources Law, [online] 34(1), pp.16–26. doi: https://doi.org/10.1080/02646811.2016.1133983.

2. Farhana, Kaniz, et al. “Energy Consumption, Environmental Impact, and Implementation of Renewable Energy Resources in Global Textile Industries: An Overview towards Circularity and Sustainability.” Materials Circular Economy, vol. 4, no. 1, 29 Mar. 2022, https://doi.org/10.1007/s42824-022-00059-1.

3. UNEP (2019). Fashion’s tiny hidden secret. [online] UN Environment. Available at: https://www.unep.org/news-and-stories/story/fashion's tiny hidden secret.

4. Palacios-Mateo, C., van der Meer, Y. and Seide, G. (2021). Analysis of the polyester clothing value chain to identify key intervention points for sustainability. Environmental Sciences Europe, [online] 33(1). Available at: https://enveurope.springeropen.com/articles/10.1186/s12302-020-00447-x.

5. www.formula4media.com. (n.d.). Achieving Net-Zero - Textile Insight. [online] Available at: https://www.formula4media.com/articles/achieving-net-zero.

6. Thakker, V. and Bakshi, B.R. (2024). Mapping the path to a net-zero chemicals industry by long-term planning with changes in technologies and climate. AIChE journal. doi:https://doi.org/10.1002/aic.18381.